Eclipses through the Centuries - Portal do Professor

Eclipses through the Centuries - Portal do Professor

Eclipses through the Centuries

Norma Teresinha Oliveira Reis


Brazilian Ministry of Education - MEC, International Space University - ISU,

Intern at NASA Goddard Space Flight Center, Summer 2008

1. Introduction

“To the best of our knowledge, our Sun is the only star proven to grow


- Philip Scherrer 1

Other than Earth itself, the Sun and Moon are the celestial bodies most closely

related to human reality. Although people in ancient times were curious about

the stars and the universe as a whole, the Sun and the Moon have been the

main actors in our celestial theater. Since they are most directly associated

with quotidian issues such as the day and night cycle, as well as the seasons,

they influence vital human economic activities such as agriculture.

The Sun is crucial to us all. It is by far the closest star to the Earth and our

ultimate source of warmth, light and energy. Could you imagine life on Earth

without the Sun?

Fig. 1 – The Changing Sun. These 13 x-ray images, obtained by the Yohkoh

spacecraft between 1991 and 1995, provide a dramatic view of the Sun, highlighting

how the solar corona changes during the waning part of the solar cycle as the Sun

goes from an “active” state (left) to a more passive state (right). Source: NASA.


Fig. 2 – Lunar eclipse in Athens, Greece,

January 9, 2001. Multiple exposure

technique shows an eclipsed Moon, which

during totality assumes a deep red color.

Credit: © 2002, photo by Fred Espenak.

Early civilizations depended deeply on the

Sun. That time, the Sun was essential to

estimate the time of day. For this purpose,

the Chaldean astronomers developed the

gnomon (a shaft erected perpendicular to

the horizon), used to indicate the passing

hours through its shadow projected on the

ground. Ancient people also studied the

Sun’s cycles in order to know when to plant

crops, to get ready for winter, as well as

to plan ceremonies related to the changing

seasons. Can you figure out when seasons

are about to change?

People in early times were usually fearful

of eclipses of the Sun and Moon. Indeed,

humans are sometimes frightened by the

unknown and by whatever they cannot

understand or predict. Imagine a spaceship

landing in your backyard with creatures

from another world – this would be most

frightening! If we had no prior knowledge about the Sun’s disappearance in

broad daylight during a solar eclipse (resulting from the temporary passage of

the Moon between the Earth and our star), we would fear that the Sun’s light

has been truly lost, and that such darkness might last forever.

Eclipses are ineffable astronomical phenomena that have provoked human

curiosity, fear, passion, and other strong feelings throughout the course of

history. In this paper, you will learn more about solar and lunar eclipses, along

with their influence in early and current societies.

Before discussing further on eclipses, let us better understand the subjective and

objective meanings of the Sun in early epochs. Ancient civilizations feared so

much the disappearance of the Sun, in special because it ruled their economy.

Indeed, those agricultural societies needed sunlight and warmth in order to

exist. Moreover, it must have been most intriguing for early civilizations to

suddenly be deprived of the Sun’s bright light during the day. They might have

asked, “Is this the end of the world?” “Are the Gods angry with our behavior?”


Human imagination is very creative at filling in gaps of understanding.

Although the Sun was regarded as a powerful god and a cosmic hero, it also

had enemies to fight. Sometimes demons of darkness obscured the Sun, and

people wondered if their god would

not return any longer. 2 Likewise, when

a lunar eclipse occurs, the way the

full Moon is occulted in a vast area of

shadow, and the way its color changes

to a blood red certainly would indicate

some disturbance in the cosmic order.

So it would not be a large stretch to

wonder whether this was a signal of

Fig. 3 – The invisible dragon. People in ancient

China and old Southeastern Asian cultures believed

that a dragon swallowed the Sun during solar

eclipses. Source: NASA.

divine anger, or the action of some

demonic power. 3 As a consequence,

several myths associated to eclipses


As mentioned, a solar eclipse occurs when the Moon passes in front of the Sun

and obscures it totally or partially. This configuration only exists during the

new Moon phase, and then only when the Sun, Moon, and Earth are on a single

line, with the Moon in between. Since the Moon’s orbit is tilted 5 degrees to the

Earth’s orbital plane, this configuration will not happen every month.

We do not know for certain since how long mankind has witnessed eclipses.

Sequences of marks scratched on animal bones dating back 30,000 years

suggest the changing phases of the Moon from one cycle to the next. 4

Though eclipses are well understood today, the apparent disappearance of the

Sun and Moon has been attributed to different reasons through the centuries.

The ancient Chinese, for example, thought that there was an invisible dragon

in the sky. This dragon was angry with them and, for this reason, would devour

the Sun. Whenever this happened, they would follow several rituals intended

to scare the dragon away and make the Sun reappear.

One ancient Chinese tradition was to bang drums and pots and make other

loud noises during eclipses in order to frighten the dragon away. Even more

recently, in the nineteenth century, the Chinese navy fired cannons during a

lunar eclipse to scare the dragon that was eating the Moon!


In the ancient Near East, the dragon symbolized the four elements of nature:

earth, air, fire, and water. They were usually associated with dark forces, and

with the earth-dwelling serpent, representing evil. 5

The idea of a ferocious animal or beast trying to swallow the heavenly luminaries

was common to many civilizations. The battle between the powers of light and

the powers of darkness, or the voracious appetite of mythical beasts was the

basis for many explanations of eclipses.

In this paper, you will learn more about the mechanism of eclipses and discover

interesting stories about these awe-inspiring astronomical phenomena that

have changed history through the centuries, advanced science and still today

fascinate people of all ages, nationalities and cultures worldwide.

2. Some Eclipse Legends

Eclipses did not frighten some early

civilizations, though. The Eskimo and the

Aleuts, for instance, interpreted them as

signs of good fortune. The Sun and the

Moon would temporarily leave their natural

places in the sky to reassure themselves

that everything on Earth was going fine.

Some eclipse legends are love stories and

numerous others reflect local beliefs, as


a) In most Aboriginal cultures, it was

believed that the Moon and Sun were

husband and wife respectively, pulling

curtains in the sky to ensure privacy for

their union.

b) The Athenians, in ancient Greece, considered an eclipse (solar or lunar)

to be caused by angry Gods; therefore they were regarded as bad omens.

c) The Mayans, in Central America, believed that during an eclipse of the

Moon, a giant jaguar was eating it. The Jaguar moved through the darkness,


Fig. 4 – Conjugal eclipse. Some people

had a romantic view of eclipses. The Sun

and Moon are lovers who, when they

embrace, turn off the lights to assure intimacy.

Source: Bibliothèque nationale de

France (BnF), photo Jean-Loup Charmet.

and its coat seemed a starry sky.

d) In Japan, wells were closed to prevent the sky poison, hidden by the

eclipse, from falling into them. 6

e) In Scandinavia, two wolves named Skoll and Hat were believed to terrorize

the Sun and Moon.

f) In India, a dragon named Rahu, would have the head of a dragon and

the tail of a comet. It rode in a chariot drawn by eight black horses that

represented the sky.

g) The Aztecs believed that Tzitzimine were star demons who caused eclipses

when they waged battles with the Sun.

h) In Bolivia, it was believed that dogs chased after the Sun and the Moon

and the tore the Moon’s face apart with their teeth. It was the Moon’s blood

that would turn the Moon red. The people howled and wailed in order to

chase the dogs away. 7

The fact is that humanity has never been indifferent to eclipses. Through the

centuries, they have been mentioned as affecting or even determining important

historical events. Empires would rise or fall, kings would be crowned or

dethroned, and battles would be lost or won because of chance alignments of

the Sun, Earth and Moon.

3. Eclipses and the Advancement of Science

From a scientific standpoint, eclipses have often opened doors to important

knowledge. In early times, for instance, lunar eclipses constituted an important

proof of the sphericity of the Earth. Lunar eclipses were central to debates

of Pythagoras, Aristotle, and other Greek philosophers. Thus, if we have an

eclipse of the Moon by the shadow of the Earth, the shape of that shadow must

represent the profile of the planet. 8

For instance, Aristarchus (310 - 230 BCE) used eclipses to estimate the relative

sizes of the Earth and Moon by the curvature of the Moon’s disk and the

curvature of the Earth’s shadow cast on it, having the Sun, Earth and Moon

aligned in this sequence. He also estimated the distance of the Earth to the


Moon and to the Sun, as well as the size of the latter. Moreover, he demonstrated that

the Sun was more distant than the Moon and larger than the Earth. 9

By the late 1800’s astronomers realized that the corona 10 was essential to understanding

countless solar phenomena, perhaps even the mysterious auroras. In 1930, Bernard

Lyot (1897-1952 CE) invented the coronagraph, an instrument that allowed the rare

total solar eclipses to be recreated at will, and at a time and place of choosing. 11

According to Mitchell (1869), “solar eclipses, at one time the terror of the ignorant,

and the study of astronomers only, have come to be specialties also of the chemist,

the physicist, and the photographer. The telescope, the camera, and the spectroscope

work together, each crowded with work, and each finding its most fruitful field in

the Sun.” For instance, during the eclipse of August 16, 1868, Sir Joseph Lockyer

of England, and Monsieur Pierre Janssen of France independently discovered by

spectroscopic means the telltale signs of helium in the Sun’s corona. Helium became

the first chemical element to be discovered outside of Earth, taking its name from the

Greek word for the Sun — Helios.

Eclipses blot out the photosphere and reveal the presence of an atmosphere above

the Sun beyond a solar radius. This medium became a matter for extensive study

in the 19th century, and eclipse observations revealed a bright inner portion, the

chromosphere, and a very extensive halo, the corona. 12

Arguably, the most important eclipse of modern times occurred on in May 29, 1919,

when Arthur Eddington (1882-1944 CE) used a solar eclipse to test Einstein’s general

relativity theory by showing that strong gravitational fields, such as the Sun’s, are

capable of bending star light by the amount predicted.


Fig. 5 – Aristotle’s geometrical argument. Shown

in several ancient astronomy texts, including

Cosmoghaphia, by Petrus Apianus and Gemma

Frisius (1581) and Mustapha Ibn Abdullah’s Book

of the Description of the World (1732). Source:

Bibliothèque nationale de France (BnF).

Solar eclipses are used to photograph

and study the composition and

dynamics of the Sun’s corona,

which is only visible when the

Sun’s bright disk or photosphere is

completely blocked out.

Scientists also use these events to

study space weather phenomena

such as solar flares and coronal mass

ejections (CMEs). Such phenomena

are important due to the fact that

they can directly impact space

systems and human activities like

telecommunications, navigation,

and the extremely complex work of

astronauts in space, especially while performing extra-vehicular activities.

Presently, most people understand the basic mechanism of eclipses and are no

longer frightened by them. They are usually seen as beautiful and fascinating

events. Every year, people of different ages, nationalities and interests join to

watch total or partial eclipses of the Sun and the Moon all around the world.

But has something been lost? Does knowing how something works reduce its

beauty and mystery? Or is the beauty of the world deepened by understanding

the things we see?

Fig. 7 – Coronal mass ejection.

Huge bubbles of plasma ejected

from the solar corona and that can

disrupt Earth’s magnetosphere.

Credit: ESA/NASA.

These magnificent celestial spectacles are also

observed worldwide by students and teachers of

all levels, capturing youthful imagination towards

the universe and encouraging new understandings

about space. The example of the Danish astronomer

Tycho Brahe (1546-1601 CE) well illustrates that.

He made a career shift from law to astronomy

after being fascinated by an eclipse at the age

of fourteen. Before Brahe, astronomy was quite

innacurate. He then decided to develop accurate

tables for the observation of stars and planets. 13

Brahe’s contributions to astronomy have indeed


Fig. 6 - The magnificent corona. This dramatic

image is a combination of 22 photographs digitally

processed, highlighting faint features of a total eclipse

that occurred in August of 1999. The outer pictures of

the Sun’s corona were digitally altered to enhance dim,

outlying waves and filaments. Credit: © 1999, photo by

Fred Espenak.

een significant. He catalogued with great accuracy more than 1,000 stars!

Eclipses are an effective means of making people curious about the wonders

and mysteries of the universe, and they fan the fires of curiosity and the human

desire for exploration and discovery. They are a channel to unite people around

the world to look at the starry sky as the place where we all came from long

ago, cosmologically speaking.

4. Eclipses: Definitions and Terminology

The concept of a solar or lunar eclipse

being viewed as the gradual eating of the

luminary bodies by a celestial invisible

dragon is manifested in the earliest

Chinese term for eclipse, shih 14 (to eat).

They believed that eclipses happened

when this dragon attempted to devour the

Sun or the Moon. 15

The term eclipse originated from the

Greek ekleipsis, from ekleipein ‘fail

to appear, be eclipsed,’ from ek ‘out’

+ leipein ‘to leave’, also meaning

‘abandon’, ‘failure’.

According to the Oxford English

Dictionary (1969), eclipse as a noun means “an interception or obscuration of

the light of the Sun, Moon or other luminous body, by the intervention of some

other body, either between it and the eye, or between the luminous body and

that illuminated by it; as of the Moon, by passing through the Earth’s shadow;

of the Sun, by the Moon coming between it and the observer; or of a satellite,

by entering the shadow of its primary.”

In the figurative, eclipse would mean an “obscuration, obscurity, dimness; loss

of brilliance or splendour” e.g., the eclipse of an empire.


Fig. 8 – Ancient representation for eclipses

of the Sun and Moon. Atlas methodique et

elementaire de geographie, by Claude Buy

de Mornas. Source: Bibliothèque nationale de

France (BnF).

5. Scientific background

“Some people see a partial eclipse and wonder why others talk so much

about a total eclipse. Seeing a partial eclipse and saying that you have

seen an eclipse is like standing outside an opera house and saying that you

have seen the opera; in both cases, you have missed the main event.”

Fig. 9 – Eclipsed Moon in Stonehenge. A reddened Moon

appears between the stones of Stonehenge during the May

2004 total lunar eclipse. Credit: Photo by Phillip Perkins, Astro

Cruise Web site,

- Jay M. Pasachoff 16

Compared to other celestial

bodies, the Sun and Moon are

the brightest when viewed

from our home planet. For

this reason, solar and lunar

eclipses are also closer to

our realities than any other

celestial phenomenon.

Furthermore, solar eclipses

are much more notable than

lunar eclipses, because,

when total, they can “turn

day into night!” During

solar eclipses, for example,

animals become agitated

because they perceive that something is wrong about the natural order of things:

Why that sudden darkness in the middle of the day!

Eclipses are basically an alignment of at least three celestial bodies in a straight

line. 17 The term solar eclipse is a misnomer, because the phenomenon is actually

an occultation.

Why is this so? The answer is simple. An eclipse occurs when one celestial

body passes into the shadow cast by another (as with an eclipse of the Moon).

An occultation occurs when one body passes in front of another. When the new

Moon passes in front of or occults the Sun, as seen from Earth, the Moon also


casts a small shadow on the planet. An “occultation” of the Sun is thus a partial

“eclipse” of the Earth as well. 18

You will find in the sequence a set of questions and answers that will help you

better understand the mechanism of eclipses.

A) When do we have a solar eclipse?

When any part of the Earth

enters any part of the Moon’s

shadow, there is a solar

eclipse somewhere on the

planet. 19

This configuration can only

exist during new Moon, when

the Sun, Moon and Earth are

aligned with the Moon in

between. Since the Moon’s

orbit is tilted 5 degrees to the

Earth’s orbital plane, this will

not happen every month.

Fig. 10 – The geometry of a solar eclipse. Because

of this unique geometry, during a total solar eclipse the

Moon occults the Sun with a nearly perfect fit. Extracted

by permission from Fred Espenak’s Web site, http://www.

The lunar shadow is composed

of two parts: a) the outer or penumbral shadow, and b) the inner or umbral

shadow. From within the penumbra, only part of the Sun is occulted. In contrast,

the dark, central umbra is the shadow of a total eclipse. During a total eclipse,

the umbra sweeps across the Earth from west to east and the course it travels is

called the path of totality.

Anyone standing within this zone will see the Sun completely obscured by the

Moon for as much as seven minutes. Outside the path of totality but still within

the penumbra, a partial eclipse is seen. The path of the umbra is rarely larger

than 300 km wide while that of the penumbra is about 7,000 km wide. 20

B) Why do the Sun and Moon appear to be the same size during a solar


The Moon is only 3,500 km in diameter while the Sun is about 1,400,000 km


across. One of the most remarkable coincidences in nature is that the Moon

and Sun appear to be the same size when viewed from the Earth. This occurs

because, although the Sun is 400 times larger in diameter than the Moon, it is

also 400 times farther from the Earth. 21

Fig. 11 – Scheme for visibility of eclipses. (a) An eclipse occurs when Earth, Moon, and Sun are

precisely aligned. If the Moon’s orbital plane lies exactly on the plane of the ecliptic, this alignment

would occur once a month. (b) For an eclipse to occur, the line of intersection of the two planes must lie

along the Earth–Sun line. Thus, eclipses can occur only at specific times of the year. Credit: Chaisson/

Mcmillan, Astronomy Today, 6 ed., Pearson Education.


C) Why doesn’t a solar eclipse occur at every new Moon?

The Moon’s orbit around the Earth is not in the same plane as the Earth’s orbit

around the Sun. The Moon’s orbit is inclined by about 5 degrees to the Earth’s

orbital plane, which is on the ecliptic. Our planet’s natural satellite crosses

this imaginary plane only twice a month at two points called the nodes. At

other times, the Moon is either above or below the plane of the Earth’s orbit.

Complete alignments of the Sun, Moon, and Earth only happen when the new

Moon phase occurs at one of the nodes. 22

D) Are solar eclipses rare phenomena?

No. They are actually more

common than lunar eclipses. In

any one calendar year, there can

be as many as five solar eclipses.

There can be no more than three

lunar eclipses per year, and it is

quite possible to have none at

all. Combining both solar and

lunar eclipses, it is possible for

one calendar year to contain a

maximum of seven eclipses. 23

Please note that we are referring

to eclipses in general. Total solar

eclipses are relatively rare and

Fig. 12 - Geometry of the Sun, Earth, and Moon during a

total eclipse of the Sun. The Moon’s two shadows are the

penumbra and the umbra (sizes and distances not to scale).

Extracted by permission from Fred Espenak’s Web site,

happen at any given specific location on average only once in hundreds of


E) What is the most notable phase of a total solar eclipse?

The most dramatic phase occurs during totality, when the Sun is completely

obscured by the Moon. Totality never lasts more than 7 minutes 40 seconds.

During each millennium, there are typically fewer than 10 total solar eclipses

in which totality exceeds 7 minutes. Only during totality (See “The Experience

of Totality,” at can the

corona be observed without specialized equipment, so that total solar eclipses


are very important for astronomers.

F) Is it easy to predict a solar eclipse?

Yes! Today, we understand the motions of celestial bodies and can model the

forces on them with great accuracy. Computer programs fed with this knowledge

easily compute the time and geometry of eclipses well into the future or the past.

We can account for corrections due to relativity, tides, precession, and other

effects yielding accuracies of within a second of time for eclipses relatively

close to the present.

G) Are eclipses visible everywhere on the planet?

No. During a lunar eclipse, when the Moon passes through the Earth’s giant

shadow, the event is visible during the night time in one entire hemisphere

of the Earth, and totality usually lasts more than one hour. 24 However, even

the partial phase of a solar eclipse will only be visible over a portion of the

sunlit side of the Earth and totality can be seen only along a relatively thin

(approximately 60-70 miles wide) line.

Lunar eclipse geometry is shown in Fig. 13. A lunar eclipse occurs when our

planet casts its shadow on the Moon, occulting it partially or totally. The Moon

assumes a beautiful reddened color pattern when it is eclipsed by Earth. Perhaps

it is for this reason that lunar

eclipses have frightened early

civilizations who associated the

red color with blood or warfare.

Fig. 13 – Geometry of the Sun, Earth, and Moon

during a lunar eclipse. The Earth’s two shadows are the

penumbra and the umbra (sizes and distances not to scale).

Extracted by permission from Fred Espenak’s Web site,


For example, during one of

Columbus’ trips to the Americas,

he used his knowledge of a

forthcoming lunar eclipse to

obtain favors from the natives.

How? Basically, he threatened

the natives by saying that, if

they did not provide him with

the supplies he and his people

needed, his God would get

angry and darken the Moon, and

that would be followed by famine

and diseases. There are many other

interesting examples in history

of how celestial phenomena have

influenced people.

H) How many types of solar

eclipses are there?

There are three main kinds of solar

eclipses as listed in Table 1. Total

solar eclipses are rare spectacles that

only last for a few minutes and are the

only opportunity to observe the Sun’s

Fig. 15 – Artificial solar

eclipse. A spacecraft instrument,

called a coronagraph,

creates artificial solar eclipses

by blocking the Sun’s light with

an occulting disk. Credit: ESA/


Table 1 - Main types of solar eclipses.

corona without specialized equipment. Although they

occur somewhere on Earth approximately every 18

months, it has been estimated that total solar eclipses

reoccur at any given spot on average only once every

300 to 400 years. The longest total solar eclipse during

the 8,000-year period from 3,000 BCE to 5,000 CE

will occur on July 16, 2186, when totality will last 7

minutes 29 seconds. 25

In addition to the main kinds of natural solar eclipses,

astronomers are now able to produce artificial eclipses

at any time by blocking out the Sun with an artificial

mask or “occulting disk”, allowing them to study the

Sun’s faint corona.

Type Description

Partial The Sun is partially covered by the Moon.

Total The Moon completely covers the Sun.

Fig. 14 – Total lunar eclipse over Maui, July 16,

2000. Multiple exposure mode was used to capture

the entire eclipse; a second exposure captures

morning twilight. Credit: © 2000 photo by Fred


Annular The Moon’s center passes in front of Sun’s center while the Moon is near apogee.

The Moon’s angular diameter is then smaller than that of the Sun so that a ring of the

Sun can still be seen around the Moon.


I) What are transits?

Transit is a special case of eclipse, which happens with the passage of a planet

across the disk of the Sun. From the Earth, the observable transits are from

planets Mercury and Venus only.

Fig. 16 – Transit of Venus. In a village in Slovakia,

Tomas Maruska took this rare picture, showing Venus

and the International Space Station (ISS) transiting

the Sun at the same time. Credit: Tomas Maruska ©

2004. Source: NASA.

They are far more rare than solar eclipses. On the average, there are only 13

transits of Mercury each century. Transits of Venus, by its turn, usually occur

in pairs with eight years separating the two events. More than a century elapses

between each transit pair.

The first transit ever observed in History was of the planet Mercury in 1631 by

the French astronomer Gassendi. A transit of Venus occurred just one month

later but Gassendi’s attempt to observe it failed due to the fact that the transit

was not visible from Europe. In 1639, Jerimiah Horrocks and William Crabtree

became the first to witness a transit of Venus. 26

J) Can I look at the Sun with the naked eye during a solar eclipse?

Looking at the Sun is dangerous when any part of the brilliant disk of the

Sun (photosphere) is visible; this can cause permanent eye damage. This is

true at any time, including during solar eclipses. Because an eclipse offers an

unusually high temptation to look at the Sun, there is a elevated incidence of

eye damage caused during solar eclipses. Directly viewing the Sun through any

kind of optical aid, binoculars, a telescope, or even a camera’s viewfinder, can

be extremely dangerous unless certain precautions are taken.

K) How can I safely observe an eclipse?

In order to better experience the amazement of observing a solar eclipse, certain

cautions must be taken. Otherwise, what was expected to be a pleasant and


joyful experience could become a real nightmare. Here you will learn how to

proceed to safely observe a solar eclipse.

Staring at the Sun without proper protection can cause irreparable damage to

the eye and is not recommendable. The Sun is a source of electromagnetic

radiation: solar X-ray, gamma ray, microwave, radio wave, ultraviolet, and

visible light. 27 When the retina is exposed to intense visible light, two kinds

of eye damage can occur, alone or simultaneously - retinal burns and thermal

injury, the latter occur without any feeling of pain, but that can cause irreparable

damage to the eye or even blindness. 28

So how can we safely observe the Sun? There are several safe methods, but

the best one is indirect projection (See “Observing Eclipses Safely,” at This can be done by

projecting the Sun’s image on a white piece of paper using a pair of binoculars

(with one of the lenses covered), or by putting a small hole (about 1 mm in

diameter) in a piece of aluminum foil taped over a paper towel tube, often

called a pinhole camera. It allows safe viewing of the Sun’s projected image.

However, care must be taken to ensure that no one looks through the projector

directly, especially if children and teenagers are present, because this would

cause severe eye damage.

The Sun can be also observed with appropriate filters to block its harmful

radiation. Other improvised methods, such as looking at a reflection on water,

or looking through a compact disk, are also dangerous. Only properly designed

and certified solar filters should be used for direct viewing of the Sun, and these

must be in perfect condition, as even a small defect could cause irreparable

damage to the eye.

Please be aware that standard or polaroid sunglasses are not solar filters.

Although they may afford some eye relief if one is outside on a bright day, you

should never use them to observe the Sun. You cannot use sunglasses, even

crossed polaroids, to stare at the sun during partial phases of an eclipse. They

provide essentially no eye protection for this purpose. 29

Strictly speaking, it is safe to observe the total phase of a solar eclipse when the

Sun’s photosphere is completely covered by the Moon. The Sun’s corona will

be visible, as will be the chromosphere, solar prominences, and possibly even

solar flares. Nevertheless, even under these conditions, there is great danger in


directly viewing the end of the total phase, and return of the “exposed” Sun,

without protection, because all parts of the Sun’s disk are of similar intensity.

Viewing a tiny sliver of the Sun could cause permanent eye damage. Actually,

the 1 percent of the solar surface still visible is about 4,000 times brighter

than the full Moon. 30 For this reason, viewing even the total phase of a solar

eclipse through binoculars, or a telescope, or even with the naked eye, is not


In summary, it is completely safe to observe solar eclipses, provided that the

necessary precautions are taken. For this purpose we strongly recommend

the use of indirect projection for a safe observation. We encourage you to

cautiously enjoy the delightful experience of observing this awe-inspiring

phenomenon that has both amazed and frightened people, changing the course

of history through the centuries, as you will discover in the following pages.

6. Eclipses and History

“We had the sky up there all speckled with

stars, and we used to lay on our backs and

stare up at them and wonder about whether

they was made or only just happened.”

- Mark Twain 31

Since the very beginning of History, people have

been amazed by what they see when they look up

at the sky. Indeed, looking at the celestial sphere

without the unpleasant interference of city lights

is magnificent. It can sometimes mesmerize

us with a deep desire of traveling out to those

celestial spheres to directly experience what our

eyes cannot reach. Human imagination has no

boundaries, but the universe is infinite! However,

most ancient civilizations have viewed changes

in the sky with great fear and apprehension.

Comets, meteor showers, supernovae, lunar and


Fig. 17 – Desolation des Peruviens

pendant L’Eclipse de Lune. Voyage

Historique de l’Amerique Meridionale.

The Spanish explorer Don Juan

described the Peruvians despair during

an eclipse. Source: The Philadelphia

Print Shop Ltd., Web site, http://www.

solar eclipses were viewed as bad omens by most societies.

As we discussed previously, the Sun and the Moon are the main actors in our

celestial theater, the former being vital for life on Earth. The Moon, by its turn,

has served as special inspiration for poets, writers, and lovers. The Sun and

Moon have also been associated with religion and mythology, and sometimes

regarded as gods with influence on the destiny of both societies and individuals.

It is our nature as human beings to attribute meaning to events by whatever

history, tradition or thought is available to us. The same is true for eclipses

throughout the centuries.

Solar and lunar eclipses were usually regarded as a disturbance in the natural

order of the sky - as an indication that something was going wrong. Several

historical events coincided with solar or lunar eclipses: battles, crowning or

dethroning of emperors, peace treaties, and so forth.

Unlike comets, which for a long time were regarded as unpredictable events,

eclipses were accurately predicted at the earliest stages of mankind’s history. 32

Early astronomers were able to predict eclipses by around 2300 BCE. Their

predictions were based on empirical relationships, governing the recurrence of

events by which the relative positions of the Earth, Sun, and Moon reoccur the

same way after 6,585 days. The existence of a regular eclipse cycle, such as the

Saros cycle, resulted from these coincidences involving complex combinations

between the movements of the Moon, Earth, and Sun. This more detailed

knowledge of eclipses started to be acquired during the second century BCE,

the golden age of Greek astronomy.

However, the general population did not understand these relationships. As

governors began to realize the influence astronomical phenomena exerted

over the population, they used this knowledge as an instrument of power to

influence people’s psyche. The population would follow rituals and say prayers

in order to prevent the supposed dire effects. Governors wanted to pretend they

could influence the obscure powers involved, and likewise, astrologers and

astronomers sometimes attempted to use their knowledge to manipulate and

influence governors.

Only in the last five hundred years or so, or certainly since the invention of

the telescope in 1609, have we come to understand these cosmic concurrences

primarily in terms of the natural order of the universe. As previously mentioned,


these events are usually no longer feared, but regarded as singular opportunities

to better understand the universe.

In this article, we present some important solar and lunar eclipses, and their

impact on people, societies, and science through the centuries.

Ancient History

1) Ho and Hi, the Drunk Astronomers, 2137 BCE

Ancient Chinese astronomy was primarily a governmental activity. It was

the astronomer’s role to keep track of solar, lunar and planetary motions, and

explain what they meant to the ruling emperor.

Throughout the centuries, Chinese astronomers devoted substantial attention

towards predicting eclipses. Nevertheless, like all similar efforts prior to the

Renaissance, this could only be empirical. 33

The earliest record of a solar eclipse comes from ancient Chinese history.

Identifications of this

event have varied

from 2165 – 1948

BCE, 34 though the

favored date is Oct.

22, 2137 BCE.

According to a

legend, the Chinese

royal astronomers

Ho and Hi dedicated

too much time to

consuming alcohol

and failed to predict

the forthcoming

eclipse. Traditionally,

this solar eclipse was

Fig. 18 – Eclipse observation in China around 1840. Astronomers

calmly observe an eclipse and the servants, terrified, prostrate

themselves on the ground to placate the bad omen. Credit: History of

China and India © Mary Evans/ Explorer. Source: Brunier and Luminet,

Glorious Eclipses, Cambridge University Press.


ecorded in the Shu Ching (Historical Classic), and regarded as from the 3rd

millennium BCE. “On the first day of the month, in the last month of autumn,

the Sun and the Moon did not meet (harmoniously) in Fang”… so runs the

text. 35

The emperor became very unhappy because, without knowing that there was

an eclipse approaching, he could not organize teams to beat drums and shoot

arrows in the air to frighten away the invisible dragon. The Sun did survive,

but the two astronomers did not have the same luck, and lost their heads for

such negligence. This verse, whose author is unknown, well illustrates such

tragedy:“Here lie the bodies of Ho and Hi/ Whose fate though sad was visible/

Being hanged because they could not spy/ Th’eclipse which was invisible.”

Since then, a legend arose that no one has ever seen an astronomer drunk during

an eclipse. 36

2) Eclipse of Abraham in Canaan, 1533 BCE

See Visibility Map:

“And when the Sun was going down...

great darkness fell upon him.”

Eclipses are also mentioned in sacred

books such as the Christian Bible.

One of the best-known references to

eclipses appears in the book of Genesis,

involving the journey of Abraham into

the land of Canaan.

It is possible to relate such description

with a computed solar eclipse

occurring on May 9, 1533 BCE. 37 Fig. 19 – Abraham journeying into Canaan. This

image was produced by the French artist Gustave

Dore and illustrates the journey into Canaan.

Credit: Public domain.


3) Homecoming of Odysseus, 1178 BCE

See Visibility Map:

“. . . and the Sun has perished out of heaven,

and an evil mist hovers over all.”

- Homer, the Odyssey 38

The king of Ithaca Island, Odysseus, has been persuaded to go to the Trojan

War, which lasted ten years. When Troy fell, the Greeks went back home.

However, Odysseus’s enemy, the god of the sea Poseidon became angry with

him, making that difficult for him to return home.

Odysseus is the hero from Homer’s Odyssey, and could have returned to his

Penelope on day of eclipse. That should have been a very beautiful eclipse,

during which all planets were visible simultaneously, and the hidden Sun was

“crowned” by the Pleiades. 39

Basically, we have three evidences to sustain such hypothesis:

a) Plutarch and Heraclitus interpreted a passage in the 20th book of Odyssey

to be a poetic description of a total solar eclipse at Odysseus’ return;

b) A century ago, astronomers estimated that such eclipse occurred over

the Greek islands on April 16, 1178 BCE, the only one in the region close

to the probable date of the fall of Troy;

c) Recently, astronomical references led two scientists to suggest that the

eclipse of 1178 BCE possibly coincided with the homecoming of Odysseus.

Almost all classic scholars are skeptical of this correlation. If there was an

eclipse, Homer must have had it in mind when he wrote of a seer prophesying

the death of Penelope’s waiting suitors and their entrance into Hades. The story

actually does not mention an eclipse, but omens and a poetic description of a

total solar eclipse.

The story tells that Odysseus arrived home wearing beggar’s clothes and hiding

before revealing himself. It happens that, when Penelope’s suitors sat down at

noon for a meal, they started laughing and saw their food spattered with blood.

At this moment, the seer Theoclymenus foretells their death: “The Sun has

been obliterated from the sky, and an unlucky darkness invades the world.”


This description suggests a solar eclipse over Ithaca. As a matter of fact,

Odysseus killed Penelope’s suitors, who were planning to steal his throne and

his wife, and spent a long night of love with his wife. 40

4) The Old Testament Eclipse, 763 BCE

See Visibility Map:

One passage in the Christian Bible says: “And on that day, says the Lord God:“I

will make the Sun go down at noon, and darken the Earth in broad daylight.”

The corresponding eclipse should have occurred on June 15, 763 BCE.

A cross-reference is provided by an Assyrian historical chronicle known as the

Eponym Canon. In Assyria, each year was named after a ruling official and the

year’s events were recorded under that name in the Canon.

Under the year corresponding to 763 BCE, a scribe at Nineveh wrote this

simple line: “Insurrection in the City of Assur. In the month of Sivan, the Sun

was eclipsed.” Historians have thus been able to use this eclipse to improve the

chronology of early biblical times. 41

5) Archilochus Eclipse, 648 BCE

Fig. 20 – Penelope’s suitors, by John William

Waterhouse (1912). While Odysseus struggled

to return home after the Trojan War, his throne

and his wife were being disputed. But Penelope

decided to wait for his husband. Credit: Public


See Visibility Map:

It is believed that the Greek lyric poet Archilochus witnessed a total solar

eclipse, which happened on April 6, 648 BCE. 42 Delighted, he said: “Nothing

there is beyond hope, nothing that can be sworn impossible, nothing wonderful,


since Zeus father of the Olympians made night from midday, hiding the light of

the shining sun, and sore fear came upon men.”

6) Thales Eclipse, 585 BCE

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Is an eclipse capable of drastically changing the course of history? This story

refers to the final battle of a fifteen-year war waged between the Lydians and

the Medes. Also known as the “Battle of the Eclipse,” it occurred at the Halys

River, Turkey, and was suddenly terminated on May 28, 585 BCE, 43 due to a

total solar eclipse, interpreted as an omen indicating that the Gods wanted the

fight to stop.

In the West, the first prediction of a solar eclipse

is associated with the Greek philosopher Thales

of Miletus (624-547 BCE) who, according to

Herodotus (490-425 BCE), foretold this eclipse. 44

“In the sixth year a battle took place in which

it happened, when the fight had begun, that

suddenly the day became night. And this change

of the day Thales the Milesian had foretold to

the Ionians laying down as a limit this very year

in which the change took place. The Lydians

however and the Medes, when they saw that it

had become night instead of day, ceased from

their fighting and were much more eager both

of them that peace should be made between


Although it is argued that Thales used the Babylonian Saros 45 period of 223

lunations, 46,47 it is today agreed by historians that the Saros period was not

discovered before the fifth or fourth century BCE, therefore Thales could not

have used that time system.

Considering that the exact dates of eclipses can be calculated, this battle is

the earliest historical event for which a precise date is known. Thales was

proclaimed a wise man by the oracle of Delphi in 582 BCE, possibly due to this


Fig. 21 – Battle of Halys. Source:

Wisdom Portal Web site, http://

prediction credited to him. However, it is evident that Thales did not understand

the scientific basis of the phenomenon.

7) Olympic Games, 413 BCE

See Visibility Map:

Either success or failure could be sides of the same coin. They usually result

of someone’s beliefs, here associated with an eclipse of the Moon, which

frightened an entire army who believed that would indicate a bad omen for

them. This eclipse occurred on August 14, 413 BCE, during the 91st Olympiad

and influenced a battle in the Peloponnesian War.

Both the Carthaginians and the Greeks had settled parts of the south coast of

Sicily, resulting in permanent conflicts. 48 The Athenians were ready to move

their forces from Syracuse when the Moon was obscured, bringing disastrous

consequences to an Athenian army thanks to the lack of decisive leadership

by Nicias, the commander. The Athenian army was confronted in Sicily by

the Syracusan army and, having somehow failed, they embarked and left the

island. Read this excerpt from by Plutarch, in Life of Nicias:

“Everything accordingly was prepared for embarkation, and the

enemy paid no attention to these movements, since they did not expect

them. But in the night there happened an eclipse of the Moon, at which

Nicias and all the rest were struck with a great panic, either through

ignorance or superstition. As for an eclipse of the Sun, which happens

at the Conjunction, even the common people had some idea of its being

caused by the interposition of the Moon; but they could not easily form

a conception, by the interposition of what body the Moon, when at

the full, should suddenly lose her light, and assume such a variety of

colors. They looked upon it therefore as a strange and supernatural

phenomenon, a sign by which the Gods announced some great calamity.

And the calamity came to pass, but only indirectly was it caused by the

Moon.” 49

Indeed, soldiers and sailors were very frightened by this celestial omen and were

reluctant to leave. Nicias consulted the soothsayers and postponed the departure

for twenty-seven days. This delay gave an advantage to the Syracusans, who


defeated the entire Athenian fleet and army, killing Nicias. 50

8) Eclipse of Alexander, 331 BCE

Fig. 22 – The battle at Arbela, Alexander versus

Darius. Credit: Public domain.

Plutarch, in Life of Alexander:

Eclipses are sometimes interpreted as

lucky signals coming from the sky.

This was the case with Alexander

the Great (356-323 BCE) after

conquering Egypt. He marched

east and pushed the Persians out of

Babylonia, pursuing them north into

Assyria. 51

Just some eleven days before the

victory of Alexander over Darius, in

Arbela, Assyria, Plutarch and Pliny

mention that the Moon had been

totally eclipsed. See this excerpt of

“There happened an eclipse of the Moon, about the beginning of the

festival of the great mysteries at Athens. The eleventh night after that

eclipse, the two armies being in view of each other, Darius kept his men

under arms, and took a general review of his troops by torch-light.”

This unexpected occurrence seems to have created considerable tumult in an

alarmed Assyrian camp, a fact noticed by Alexander. His friends suggested

an attack on the enemy’s camp at night, but Alexander preferred that the

Macedonians should have a good night’s rest.

It was then that he uttered the celebrated answer, “I will not steal a victory.”

The eclipse happened on September 20, 331 BCE, and the celebrated Battle of

Arbela, by its turn, was fought on October 1st, 331 BCE. 52

The Greek knowledge of eclipses was largely derived from the Babylonians

after 330 BCE, so probably Alexander obtained that information with the expert

Babylonian astronomers. 53


9) Ceasar Eclipse, 51 BCE

See Visibility Map:

Julius Caesar (100-44 BCE) died in 44 BCE and Arago associated his death

with an annular eclipse of the Sun. Pliny, Plutarch and Tibullus describe that;

Seneca and Suetonius add a comet to make the story more impressive.

Shakespeare used it for his dramatic purposes. 54 When he was writing, the

belief that God intervened in the world to punish individuals or nations for

their sins was strong, so it is reflected in his writing, such as in the excerpt

below, from Hamlet 1.1:

“In the most high and palmy state of Rome,

A little ere the mightiest Julius fell,

The graves stood tenantless, and the sheeted dead

Did squeak and gibber in the Roman streets:

As, stars with trains of fire and dews of blood,

Disasters in the sun; and the moist star,

Upon whose influence Neptune’s empire stands,

Was sick almost to doomsday with eclipse.”

Actually, there was no eclipse when Caesar passed away. The factual record

is that about the time of the great warrior’s death there was an extraordinary

dimness of the Sun. Johnson suggests that Arago should have confused the

record of an eclipse with some sort of meteorological interference. 55 Suetonius

also implies that the event had a meteorological origin, so that may be regarded

as some type of cloud formation.

Nonetheless, we know accurately the day Caesar crossed the Rubicon, seven

years before his death, on March 7, 51 BCE, because that was the only possible

eclipse corresponding to the one mentioned by Dion Cassius. 56

10) Augustus’ Eclipse, 14 CE

Soon after the death of Augustus, Tacitus mentions a lunar eclipse, which has

been identified with the eclipse of September 27, 14 CE. Soldiers thought the

phenomenon was associated with their adventures, favoring their efforts. They


elieved that if they made much noise they could have the eclipse to favor them.

Tacitus says: “The Moon in the midst of a clear sky became suddenly eclipsed;

the soldiers who were ignorant of the cause took this for an omen referring

to their present adventures: to their labors they compared the eclipse of the

planet, and prophesied ‘that if to the distressed goodness should be restored

her wonted brightness and splendor, equally successful would be the issue of

their struggle.’ Hence they made a loud noise, by ringing upon brazen metal,

and by blowing trumpets and cornets; as she appeared brighter or darker they

exulted or lamented.” 57

11) The Crucifixion Eclipse, 33 CE 58

See Visibility Map:

h t t p : / / e c l i p s e . g s f c . n a s a .



Jesus Christ should have been

crucified on day of eclipse,

during the period when Pontius

Pilate was procurator of Judea

(26-36 CE). However, there is no

consensus on the date. According

to the evangelists, Jesus was

crucified on a Friday afternoon,

some hours prior to the beginning

of the Jewish Sabbath. Evidence

suggests April 3, 33 CE, 59 while

others suggest April 7, 30 CE.

Another hypothesis is that of a

solar eclipse visible at Jerusalem

on November 24, 29 CE. 60 The

Greek historian Phlegon mentions

this eclipse in his History of

the Olympiads, and says that

it has been accompanied by an

earthquake. 61 “In the fourth year

Fig. 23 – The crucifixion eclipse. According to the

evangelists, the Sun darkened during the crucifixion of

Christ. Later, the event was associated with an eclipse that

was visible at Jerusalem. Credit: © Valenciennes, Musee

des Beaux Arts, photo R.G. Ojeda.


of the 202nd Olympiad, there was an eclipse of the Sun which was greater than

any known before and in the sixth hour of the day it became night; so that stars

appeared in the heaven; and a great Earthquake that broke out in Bithynia

destroyed the greatest part of Nicaea.” In fact, mention is also made in the

Bible to the Sun being darkened earlier that day: “The Sun shall be turned into


However, there are also various allusions in the Bible to the Moon being dark

and turned to blood when it rose in the evening after the crucifixion, which

sounds like a lunar eclipse. In Acts of the Apostles, Peter also refers to a Moon

that is the color of blood and a darkened sky. There is other evidence that on

that day the Moon appeared like blood.

A New Testament Apocryphal fragment, the so-called Report of Pilate, states

“Jesus was delivered to him by Herod, Archelaus, Philip, Annas, Caiphas, and

all the people. At his crucifixion the Sun was darkened; the stars appeared

and in all the world people lighted lamps from the sixth hour till evening; the

Moon appeared like blood.” 62 This may be the result of a dust storm caused by

the khamsin, a hot wind coming from the south. Under such circumstances, a

lunar eclipse while there is much suspended dust, one would expect the Moon

to appear the dark crimson of blood. 63

The reason why the Moon is blood red is that, although it is geometrically in

the Earth’s shadow, sunlight is refracted through the Earth’s upper atmosphere,

where normal scattering will prevent blue light from penetrating. But this

refracted light would be much weaker than direct light from even a small

portion of the Sun and the blood color associated with the eclipse would not

be visible to the unaided eye. However, the Moon would have an amber color

from atmospheric absorption, similar to any other occasion when the Moon is

low in the horizon. 64

As mentioned, there is controversy among researchers whether that was a solar

or a lunar eclipse, and also controversy about the date. In any case, an eclipse

occurring in the very same day of the crucifixion would have been interpreted

by believers as a supernatural sign and influenced the change of mind of the

Jews and Pilate towards the body of Christ, leading to the placing of a military

guard on the tomb. 65


12) Muhammad’s Eclipse, 632 CE

Middle Ages

See Visibility Map:

In ancient times, births and deaths of leaders were correlated to celestial omens.

However, Islamic theology did not believe that God sent an eclipse as an

omen of its prophet’s birth, Muhammad. Some eclipses have been historically

associated to him, though.

Muhammad was born in Mecca in the Year of the Elephant, CE 569-570.

His birth year got its name from an invasion by the Abyssinians, who used

elephants in the assault. The Year of the Elephant was also memorable because

of its solar eclipse.

Afterwards, when Muhammad’s infant son Ibrahim died tragically on January

22, 632 CE, the Sun was eclipsed. Some Meccans said it was a sign from God,

but Muhammad said “The Sun and Moon are signs of God and do not eclipse

for the death or birth of any man.”

Another solar eclipse related to Muhammad occurred 39 years after his death.

In 661 CE, Mu’awiyah became leader of the empire after a revolt against Ali,

the son of Muhammad’s chief Meccan enemy. Mu’awiyah decided to transfer

the prophet’s pulpit from Medina to his capital in Damascus, Syria. As his men

were removing it, stars became visible in a dark sky. It was considered a sign

of divine anger and the relic remained in Medina as a symbol of Mu’awiyah’s

failure. 66

13) The Eclipses of Tatwine and Beda, 734 CE

An Anglo-Saxon Chronicle records that on January 24, 734 CE, 67 “the Moon was

as if it had been sprinkled with blood, and Abp. [Abp. denotes “Archbishop”]

Tatwine and Beda died and Ecgberht was hallowed bishop.” The inference

apparently is that the Moon was somehow connected with the deaths of the


two ecclesiastics. It is clear from the description of the Moon on that occasion

that it exhibited the well-known coppery shade that is a recognizable feature of

many lunar eclipses.

14) European Eclipses, 828 CE

Two lunar eclipses were observed in Europe in 828 CE, the first on July 1, very

early in the morning, and the second in the morning of Christmas day. Totality

occurred after midnight. 68

The event has been associated with the following fact, described by the Anglo-

Saxon Chronicle: “In this year the Moon was eclipsed on mid-winter’s Massnight,

and the same year King Ecgbert subdued the kingdom of the Mercians

and all that was South of the Humber.”

15) Solar Eclipse of the Emperor Louis, 840 CE

See Visibility Map:

This is the story of the

Eclipse that influenced

the division of Europe

as we know it today.

Louis of Bavaria, the

son of Charlemagne,

was head of a great

empire when, on

May 5, 840 CE, he

witnessed a solar


His imagination

worked hard against

him. Indeed, he

interpreted the

Fig. 24 - The Treaty of Verdun. Source: Northvegr Foundation, http://

phenomenon as a finger pointed at him. He took fright and never recovered,

believing that his days must be numbered. Sure enough, he died a month later. 69


“In the third year of the Indiction, the Sun was hidden from this world

and stars appeared in the sky as if it were midnight, on the third day

before the Nones of May (May 5) during the Litanies of Our Lord.” 70

After this, his three sons began to dispute his succession. Their quarrel was

settled three years later with the Treaty of Verdun, dividing Europe into three

large areas, namely France, Germany and Italy. 71

16) King Henry’s Eclipse, 1133 CE

See Visibility Map:

Visible in England and Germany, this total solar

eclipse occurred on August 2, 1133 CE, and

prompted many descriptions in the chronicles of

both countries.

For the English, the eclipse took place on the

day after the departure of King Henry I, being

interpreted as an omen of his death. In fact, he died

shortly afterwards in Normandy, subsequently

confirming the superstition. As for the Germans,

they associated the darkening of the Sun to the

sack of the city of Augsburg and the massacre of

its inhabitants by Duke Frederick. 72

The Anglo-Saxon Chronicle mentions in 1135 CE:

“In this year King Henry went over sea at Sammas, and the second day

as he lay and slept on the ship the day darkened over all lands; and

the sun became as it were a three-night-old moon, and the stars about

it at midday. Men were greatly stricken and affrighted, and said that a

great thing should come hereafter. So it did, for the same year the king

died on the following day after Saint Andrew’s mass day, December 2,

in Normandy.”

Actually, the eclipse occurred two years before the King’s death, just after his

final departure for France. 73


Fig. 25 - King Henry I. Credit:

Public domain.

17) A Witch’s Eclipse, 1349 CE

Eclipses have also been used through the centuries to trick ordinary people

who ignored the science behind the phenomenon. This was the case of a lunar

eclipse occurring on June 30, 1349 CE, visible in London. A “smart” witch

tried to use that to threaten people to provide her with what she asked for.

According to Archdeacon Churton,

“The worthy Archbishop Bradwardine, who flourished in the reign of

the Norman Edwards, and died A.D. 1349, tells a story of a witch who

was attempting to impose on the simple people of the time. It was a

fine summer’s night, and the Moon was suddenly eclipsed. ‘Make me

good amends,’ said she, ‘for old wrongs, or I will bid the Sun also

to withdraw his light from you.’ Bradwardine, who had studied with

Arabian astronomers, was more than a match for this simple trick,

without calling in the aid of the Saxon law. ‘Tell me’, he said, ‘at what

time you will do this, and we will believe you; or if you will not tell me

I will tell you when the Sun or the Moon will next be darkened, in what

part of their orb the darkness will begin, how far it will spread, and

how long it will continue’.” 74

Evil plans like that sometimes just do not work, and the presence of Bradwardine

should have made that lady just unhappy.

18) The Black Hour, 1433 CE

See Visibility Map:

One of the most celebrated eclipses of the Middle Ages was called the “Black

Hour.” It happened in Scotland and it has been said that darkness came about

3 pm on June 17, 1433 CE, and was very deep. 75

The eclipse is said to have been unusually extensive, lasting around one hour.

The scientific explanation relates to a specific angle between the Sun and Moon

that day: at the time of the eclipse, the Sun was only two degrees from perigee

and the Moon no more than thirteen degrees from apogee. 76

Some other interesting facts about this eclipse is that records of the epoch

relate that nothing was visible during the height of totality – although it sounds


exaggerated – and in the context of a very superstitious time, the pestilence that

then prevailed has been attributed to the eclipse.

19) Fall of Constantinople Eclipse, 1453 CE

The Roman Emperor Constantine, in 324 CE, moved the capital of his realm to

ancient Byzantium, which he renamed Constantinople. This capital has ruled

the eastern Mediterranean and the Black

Sea region for more than a thousand years,

providing a strong government and the

continuation of the Roman Empire after

it collapsed elsewhere. 77

By the 15th century, the Ottoman Empire,

in a large expansion, set out to conquer

Constantinople. The Turks laid siege to

it in 1402 and 1422, without success,

the city being surrounded by its famous

impenetrable walls. In 1453, the troops of

Sultan Mohammed II returned to the walls.

In addition to 250,000 men, the Turks

brought a new eight-meter long cannon,

capable of firing 600-kg cannonballs.

Despite everything, the city’s defenders, scarcely 7,000 men in number, repelled

three assaults and repaired their damaged walls each night. They were confident

in old predictions, according to which Constantinople would never fall. The

full Moon rose in eclipse on May 22 and their morale collapsed. Six days later,

Mohammed II tried a new assault and succeeded, routing the defenders.

A postern gate had been accidentally left open and some Turks entered the

city. As the Sultan’s men crossed the walls, the fight turned into a tumult and

Constantinople’s defense collapsed. The terrible sack of Constantinople that

followed lasted three days and was a major shock to western civilization. 78 The

eclipse had been seen as a bad omen by the Constantinople side and influenced

their losing the battle.


Fig. 26 – The Siege of Constantinople.

Scene from the battle of defense of Constantinople,

painted in 1499, in Paris. Credit: Public


Modern Ages

20) Christopher Columbus’ Eclipse, 1504 CE

After a long trip to the Americas in 1503 CE, in his fourth voyage, Columbus was

stranded on the island of Jamaica. In principle, he managed to obtain provisions

from the Caciques natives in exchange for some trinkets and rubbish. As the

months went by, novelty and hospitality started to decrease and also the sailors

started to become aggressive with the natives to obtain food. Upset, the Indians

communicated to the Spanish that they would not provide any more supplies.

Fig. 27- Columbus impressing the natives. This illustration from

Camille Flammarion’s Astronomie Populaire shows how Christopher

Columbus used an eclipse of the Moon to assert his power over the

Indians in Jamaica. Credit: © photo Jean-Loup Charmet.

Desperate with the threat of famine, Columbus came up with an ingenious

plan. He checked his Calendarium, which contained predictions of lunar

eclipses for several years. In particular, it predicted a total eclipse of the Moon

on the Antilles on February 29, 1504 CE. That evening, Columbus invited the

Caciques onboard his Capitana for a serious conversation. He told them that


they were Christians and their God did not appreciate the way they had been

treating them and would punish the Indians with famine and pestilence and, as

a sign of dissatisfaction, he would darken the Moon.

As soon as he said that, the Earth’s shadow started to cover the white disk.

Terrified, the natives begged Columbus to bring back the light. According to

Ferdinand Columbus (second son of Christopher Columbus), cited by Sinnot


“The Indians observed this [the eclipse] and were so astonished and

frightened that with great cries and lamentations they came running

from all directions to the ships, carrying provisions and begging (…)

and promising they would diligently supply all their needs in the


He replied that he needed to consult his God. He shut himself in a cabin for

nearly two hours. Just before the end of totality, he reappeared and announced

that God had given his pardon, and would bring them back the Moon provided

that the Christians were given provisions. Immediately, the Moon reappeared.

Astonished, the natives provided Columbus and his crew their needed provisions

until they were able to return to Europe. 79

The use of eclipses as a tool to manipulate populations less knowledgeable

about eclipses is also present in diverse works of fiction. In 1889, Mark Twain

published A Connecticut Yankee in King Arthur’s Court, a novel envisioning life

in the sixth-century England. The author has Hank Morgan, the yankee in the

title, hoodwinking the ignorant folk of that era by invoking prior knowledge of

a solar eclipse on June 21, 528 CE. Twain has Morgan, who is jailed awaiting

execution, threaten King Arthur with a blanking out of the Sun: 80

“Go back and tell the king that at that hour I will smother the whole

world in the dead blackness of midnight; I will blot out the Sun, and he

shall never shine again; the fruits of the Earth shall not rot for lack of

light and warmth, and the peoples of the Earth shall famish and die, to

the last man!” 81

The description provided by Twain is accurate in many senses, except for the

fact that there was no solar eclipse at all visible in England in 528 CE. There

are more examples of this theme in literature, such as The Adventures of Tintin

by Georges Remi and King Solomon’s Mines by H. Rider Haggard.


21) Cartographic Eclipse, 1706 CE

See Visibility Map:

This eclipse was of high interest to scientific geographers who relied on

astronomical calculations to produce terrestrial maps. The moment of the

eclipse became a cartographic point of reference, so that maps represented the

world as it was in 1706 CE. 82

From the tops of the Swiss mountains, at Montpellier, and other places in

Europe, several stars were observable at the naked eye at the time of full moon,

such as the Aldebaran and Capella, as well as the planets Venus, Mercury and


This eclipse caused great commotion. It is said that at Geneva the Council was

compelled to close their deliberations, as they could see neither to read nor

write. In several places people prostrated on the ground and prayed, wondering

the Day of Judgment had come.

Animals are also sensitive to these changes in the sky. Actually, in that day bats

were flying, fowls and pigeons flew hastily to their roots, cage-birds become

silent, hiding their heads under their wings, and animals at labor in the fields

stood still. 83

22) Edmond Halley’s Eclipse, 1715 CE

See Visibility Map:

Fig. 28 – The solar eclipse of 1715. Visible as partial at Paris, it provided the chance to observe

the event in various ways: directly through telescopes, smoked glass, pinholes, sieves, and

various filters, or indirectly by reflection in a bucket of water. Source: Bibliothèque nationale de

France (BnF).


“A few seconds before the Sun was all hid, there discovered itself round the

Moon a luminous ring about a digit, or perhaps a tenth part of the Moon’s

diameter, in breadth. It was of a pale whiteness, or rather pearl-color, seeming

to me a little tinged with the colors of the iris, and to be concentric with the


- Edmond Halley 84

This was the poetic, inspirational description of the British astronomer Edmond

Halley (1656-1742 CE) for the solar corona during the total solar eclipse of

April 3, 1715 CE, visible in England and Wales. The King of France and some

of the royal family of England should have also had observed the eclipse. 85

Halley became famous for discovering the periodicity of certain comets

and predicting their return, such as the comet he had observed in 1682 and

calculated to return after 76 years, and which was named after him. Basing his

calculations on the law of universal attraction by Newton, he provided the first

physical explanation for the appearance of these wandering bodies that had

previously terrified people. 86

23) Total Solar Eclipse of Louis XV, 1724


See Visibility Map:


This eclipse was visible in Paris on May 22,

1724 CE. The young King Louis XV, at the

time fourteen years old, observed it. The path

of its shadow, very similar to the eclipse of

August 11, 1999 CE, shifted southwards,

and crossed England, France, and Germany.

It was carefully calculated and mapped, and

painters depicted scenes of the crowds of

spectators. 87


Fig. 29 – Eclipses and the French royal


This print shows Louis XIV sitting on a

box with fan-shaped back in the center

of a sun. The numerous rays of the Sun

document indignities attributed to the

King between 1667 and 1705 as well as

the eclipse of May 12, 1706. Source: Online

Catalog, Library of Congress.

24) Banneker’s Eclipse, 1731 CE

See Visibility Map:

Benjamin Banneker (1731-1806 CE) is the first Black American scientist of

note. Born free on November 9, 1731 CE, he was son to Robert, a slave from

Guinea, West Africa, and to his free wife Mary Banneky, of English-African

descent. At that time, it was rare for Black people to be born free, but that

occurred because his mother was a free woman.

As a child, he was very curious: he enjoyed numbers, and learning how things

worked. One of his first significant projects was to build his own clock. One

day, a friend showed him a pocket watch. Benjamin was so fascinated that he

decided to make his own. After two years of work he had a totally woodenmade

clock! 88

Despite working hard to support his family, Banneker had eight years of

schooling from a Quaker teacher at an integrated private academy. He borrowed

and read books by Addison, Pope, Shakespeare, Milton, and Dryden, studied

the stars, and created and solved math puzzles as both entertainment and selfeducation.


Unarguably, his most remarkable accomplishment has been to accurately

predict the solar eclipse of April 14, 1789 CE. Other famous scientists of the

time disbelieved Banneker’s prediction, as they had their own dates; but as the

Sun was partially being covered on April 14, 1789 CE, Benjamin Banneker’

‘star’ began to shine! 90

Banneker is a brilliant example of a scientist who fought against socioeconomic

and ethnical constraints, as well as social class determinants for Black

researchers at the time, showing that barriers can and should be overcome and

giving important contributions to Astronomy.

25) Nat Turner’s Eclipse, 1831 CE

See Visibility Map:

The greatest slave revolt in North America was led by Nat Turner (1800-

1831 CE). Very clever, Turner learned how to read with his masters’ son – an

undesirable skill from the masters’ viewpoint for a slave during these times


due to fear of rebellion. Turner,

afterwards, dedicated himself to

religion and became a preacher for

his followers. 91

In 1828 CE, he had a vision: he

would lead his people to liberty,

but he should wait for a sign from

God – and it came from the sky. An

annular eclipse of the Sun occurred

on February 12, 1831 CE. Turner

interpreted it as a ‘black angel’

occulting a white one – the time

had arrived for blacks to overcome

whites, so the time had come for


Several months later, after having

murdered his original masters,

Turner and his band of insurgents headed for the small town of Jerusalem where

militiamen promptly interrupted their march. Most of the slaves, including

Turner, went into hiding for seventy days before being taken to the gallows

and hanged. 92

Many people died during this revolt, and in no other episode in American

history have a so large number of slave owners perished, a reason why Turner

is considered a hero of the resistance to oppression against black people in the

United States.

26) Adams’ Eclipse, 1851 CE

Fig. 30 – Nat Turner points at a lunar eclipse. He

foresees the rebellion that would take place with the

eclipsed Moon. Credit: Bernarda Bryson.

See Visibility Map:

The total solar eclipse of July 28, 1851 CE, was the first subject of an eclipse

expedition. The total phase was visible in Norway and Sweden, and many

astronomers from all parts of Europe traveled to those countries to observe the


Red flames were in evidence, and the fact that they belonged to the Sun and not


to the Moon was clearly established. The first photograph of the solar corona

was taken during this solar eclipse and the best observations were made in

Scandinavia. Edwin Dunkin wrote:

“The prominences were clearly visible, especially a large hooked

protuberance. This remarkable stream of hydrogen gas, rendered

incandescent while passing through the heated photosphere of the

Sun, attracted the attention of nearly all the observers at the different


The best account comes from the brilliant astronomer John Couch Adams. In

1845 CE, he calculated, at the same time as the Frenchman Le Verrier, the

position of Neptune. At this time in history, many astronomers had never

observed a total eclipse, because these phenomena rarely occurred at any given

place, and transport facilities were few and far between.

In his inspirational article that appeared in the Memoirs of the Royal

Astronomical Society, Adams’ lyrical style conveys the extraordinary emotion

of an experienced astronomer who realizes that he is a complete novice in the

arts of observing this spectacle for the first time:

“The approach of the total eclipse of July 28, 1851, produced in me a

strong desire to witness so rare and striking a phenomenon. Not that I

had much hope of being able to add anything of scientific importance to

the accounts of the many experienced astronomers who were preparing

to observe it; for I was not unaware of the difficulty which one not much

accustomed to astronomical observation would have in preserving the

requisite coolness and command of the attention amid circumstances

so novel, where the points of interest are so numerous, and the time

allowed for observation is so short.”

Adams then describes the awe-inspiring, magical appearance of the corona:

“The appearance of the corona, shining with a cold unEarthly light,

made an impression on my mind which can never be effaced, and an

involuntary feeling of loneliness and disquietude came upon me… A

party of haymakers, who had been laughing and chatting merrily at

their work during the early part of the eclipse, were now seated on the

ground, in a group near the telescope, watching what was taking place

with the greatest interest, and preserving a profound silence… A crow


was the only animal near me; it seemed quite bewildered, croaking

and flying backwards and forwards near the ground in an uncertain


In another written piece, he compares the corona with the luminous halo that

painters draw around the heads of saints. 93

27) General Gordon Fatal Eclipses, 1863 and 1885 CE

See Visibility Map:

Fig. 31 – General Gordon. Here he

wears his uniform as governor-general

of the Sudan. Source: DigNubia – Exploring

the Science of Archaeology,

An ancient Chinese aphorism says that every

dynasty starts with the replacement of an old,

degenerate regime ruled by corruption and

ineffectiveness. Nevertheless, as time goes by,

new governors, in principle virtuous, come into

the same vices and the so-called “Mandate of

Heaven” (as they reign by divine gift) is passed


In such a society, signs of the sky can significantly

influence politics. 94 The Ch’ing dynasty began

in 1644 CE, and achieved great splendor. By the

mid-19th century, however, it started to become

ineffective and corrupt.

At this time, the British general Charles Gordon

was charged by the western powers to help the

Emperor of China and his dynasty in their fight

against the Taiping revolt. Skilled with military genius and leadership, Gordon

commanded an army of Chinese mercenaries and had many victories.

On November 25, 1863 CE, a partial eclipse of the Moon frightened his troops

during the siege of Soochow (Suzhou) in Kiangsu (Jiangsu). The superstitious

Chinese interpreted the event as a bad omen for the Emperor. Soochow was not

conquered and the Taiping revolt was settled peacefully. This eclipse was thus

the cause of General Gordon’s first defeat.

Another eclipse, solar this time, on March 16, demoralized Gordon’s troops

and was directly responsible for his death. In 1885 CE, he was in charge of the


defense of Khartoum, the capital of the Sudan, under attack by a charismatic

religious leader, the Mahdi. A solar eclipse demoralized Gordon’s troops. The

city was taken before British troops could arrive with reinforcements and the

British general did not survive the massacre. 95

28) The Great Eclipse of 1878

See Visibility Map:

Considered one of the greatest

eclipse events of that century,

it is known as the great eclipse

of 1878 CE for its large path of

visibility. The Moon’s shadow

took some 20 minutes to cross

Wyoming and Colorado, in the

United States, on July 29, 1878

CE. Many tourists filled hotels

to see the spectacle - even

the famous inventor Thomas

Edison was there!

Extensive preparations were

made by officers in charge of

the National Observatory to

Fig. 32 – Capturing the corona. Magnificent pastel drawing

by E.L. Trouvelot of the total eclipse of Sun’s corona during

the May 29, 1878 eclipse. Credit: American expedition to

Wyoming; from the E.L. Trouvelot, Meudon Collection.

observe the eclipse. Five expeditions were assigned to observe the phenomenon

and conduct relevant scientific investigations, such as making drawings of the

corona, and to study the physical constitution of the Sun. 96 Although the corona

was photographed in 1851 CE, the results were not satisfactory and, in 1878,

drawings provided the best information about its size and shape. 97

The 1878 eclipse was observed by the American astronomer Maria Mitchell,

the first woman astronomer to join the prestigious American Academy of Arts

and Sciences. She led a team of five of her female students on a cross-country

journey to Denver, Colorado, to observe and scientifically report a total solar

eclipse. 98 They traveled by train at a time when ladies did not travel unescorted.

Her students were fascinated with the trip, although a little frightened.


Maria took care of all the logistics of sending telescopes to an observational

site and gave each student instructions, telling them the observations they

should make. “You will see Nature as you never saw it before – it will neither

be day nor night – open your senses to all the revelations”, she pointed out.

“Let your eyes take note of

the colors of Earth and Sky.

Observe the tint of the Sun.

Look for a gleam of light in the

horizon. Notice the color of

the foliage. Use another sense

– notice if flowers give forth

the odors of evening. Listen if

the animals show signs of fear

– if the dog barks – if the owl

shrieks – if the birds cease to

sing – if the bee ceases its hum

– if the butterfly stops its flight

– it is said that even the ant

pauses with its burden and no

longer gives the lesson to the

sluggard.” 99

Fig. 33 – Maria Mitchell. Image courtesy of the Maria Mitchell

Association. Source: Pocantico Hills Central School Web site,

She described also the most

glorious moment, that is, the

observation of the corona!

“As the last rays of sunlight

disappeared, the corona burst out all around the Sun, so intensely bright near

the Sun that the eye could scarcely bear it; extending less dazzlingly bright

around the Sun for the space of about half the Sun’s diameter, and in some

directions sending off streamers for millions of miles…”

The young ladies were enthusiastic about the experience and harbored a

brave attitude at a time when women were not supposed to be inside scientific

circles. At an epoch when men’s colleges rarely engaged science students with

direct field experience like this, Mitchell’s students were entering a new era of


learning for women. This event represented significant scientific, societal, and

pedagogical advancement promoted by a pioneering woman.

29) Eclipse of Lawrence of Arabia, 1917 CE

During the First World War, Thomas Edward

Lawrence, known as Lawrence of Arabia,

advised the Arabs in their revolt against the

Ottoman Empire. One of his greatest exploits

was the capture of Aqaba, a fortified port on

the Sinai Peninsula, with a small troop of 50


In the Seven Pillars of Wisdom, he reports

a lunar eclipse in Egypt that helped him

overcome the first defensive position,


“By my diary there was an eclipse. Duly

it came, and the Arabs forced the post

without loss, while the superstitious

soldiers were firing rifles and clanging

copper pots to rescue the threatened


Aqaba was taken a few days later. Thanks to this strategic port having fallen to

the British, the Allies soon recaptured Jerusalem and Damascus. The Turkish

soldiers had another reason to fear the eclipse: according to an Islamic tradition,

the Day of the Last Judgment is linked to an eclipse in the middle of the month

of Ramadan, and this was exactly the case on that date. 100

This is just one illustration of how eclipses through the centuries have been

recurrently associated by different civilizations to prophecies of the end of the

world. Indeed, even today there are people who do not feel very comfortable

to observe the shining solar disk being occulted by the Moon, wondering that

such event would represent far more than a mere astronomical event, and that

there would not be tomorrow.


Fig. 34 – Lawrence of Arabia. Credit:

Public domain.

30) Einstein Eclipse, 1919 CE

See Visibility Map:

This eclipse has definitively revolutionized the history of science in the

twentieth century, as it helped to confirm the General Theory of Relativity by

Albert Einstein (1879-1955 CE). Indeed, one of Einstein’s most remarkable

contributions to science was his General Theory of Relativity (GTR), formulated

between 1913 and 1916 CE. This theory contradicted Newton’s and provided

fundamental new understandings of time and space measurement. GTR was

extremelyy complex to understand though and, in order to be accepted, it

was necessary that Einstein’s theory predicted or explained some observed

phenomenon that the Newtonian theory could not. 101

In this scenario, Eddington came up with the idea that a total eclipse of the

Sun would provide such a unique opportunity to quantitatively test Einstein’s

theory. How? If it were correct, the light from stars would be bent by the strong

gravitational field of the Sun. And what circumstance was necessary to observe

this? Totality and stars appearing close-by because the test required several

bright stars close to the limb of the Sun during the eclipse. The eclipse of May

29, 1919, offered such conditions.

Fig. 35 – Total solar eclipse in Sobral, Brazil, 1919. The large city of Sobral in Ceara, Brazil, as it was

in 1919 (left), and a recent monument to celebrate the eclipse (right). Source: Sociedade Brasileira de

Fisica Web site,

The path of totality crossed Brazil, in South America, and Principe, an island

owned by Portugal in the Gulf of Guinea, just to the north of the equator and 150

miles from the African coast. In northeastern Brazil, the city of Sobral, Ceara

state, was the best post of observation of the phenomenon and two expeditions

of American and English scientists joined the Brazilians to observe the eclipse.


Their purposes were distinct. The Brazilian commission focused on studies of

the solar corona, its form and shape, and performed spectroscopic analysis of

its constitution. The American and English intended to verify experimentally

the consequences of GTR. 102

After analysis of the eclipse results, the royal astronomer Frank Dyson

announced, in November 1919 CE, that the results confirmed the theory and it

was made public: Einstein was right! In fact, what provoked such commotion

was precise measurement of the deviation of starlight passing close to the

Sun. The value of such deviation agreed with the prediction of Einstein’s GTR

(1.75 arc seconds), but was almost double the value predicted by Newton’s

gravitational theory (0.87 arc seconds).

This is one of the most dramatic events in the history of science and was

front-page news around the globe. The London Times featured the headlines,

“Revolution in science. New theory of the universe. Newtonian ideas

overthrown” and The Washington Post, with “New theory of space: has no

absolute dimensions, nor has time, say Savants.” The president of the Royal

Society, J J Thomson, described the general theory as “the greatest discovery

in connection with gravitation since Newton... Our conceptions of the fabric of

the universe must be fundamentally altered.” 103

Although people were still mystified by Einstein’s theory, his worldwide

popularity as a legendary sciencist 104 increased exponentially almost overnight 105

thanks partly to the fanfare that followed the eclipse. Einstein was also very

charismatic and became famous for his equation E=mc 2 .

31) Eclipse of End of Millennium, 1999 CE

See Visibility Map:

The eclipse of August 11, 1999 CE, was eagerly awaited and witnessed for

millions of people, many having traveled around to see the show. It covered

the Atlantic near Newfoundland, and the path of totality proceeded eastwards

to the southwestern tip of England. The Moon’s shadow then crossed France,

Germany, several eastern European countries, Turkey, the Middle East,

Pakistan, and India, before eventually reaching the Bay of Bengal. 106


Stories about the end of the world have always frightened people throughout

history. An eclipse of the Sun in the last year of the millennium would be the

perfect scenario for consternation about this issue. One key ingredient for this

eclipse was related to the forthcoming millennium, including predictions of

catastrophes. 107

32) First Eclipses of the Third Millennium, 2001 CE

See Visibility Map:

There were two eclipses opening the Third Millennium: a lunar and a solar one.

The first happened on January 9, 2001 CE, and was lunar. That was total as

viewed from most of Asia, Africa, Europe, and the eastern seaboard of North


In Nigeria, the eclipse caused great commotion, and its advent was blamed

on sinners. In the northeastern part of the country, there were rampages by

gangs of youths. Similar destruction occurred in other towns. “The immoral

acts committed in these places are responsible for this eclipse,” explained one

of the leaders of the riots.

Five months later, on June 21, 2001 CE, the first total solar eclipse of the

millennium was also witnessed in Africa. As the track passed over Angola,

Zambia, Zimbabwe, Mozambique, and finally the southern part of the island

of Madagascar, thousands of tourists and millions of local inhabitants watched

the spectacle.

Elsewhere wailing and gnashing of teeth accompanied what was considered the

“rooting of the Sun,” from which the world would not recover. 108 The world did

recover quite promptly, and we keep on waiting for the next meeting between

our two closest celestial bodies in their marvelous space ballet.

33) Eclipse seen from space, 2006 CE

See Visibility Map:

In Africa, many regard eclipses not simple astronomical phenomena, but

attribute some metaphysical meaning to them, usually related to prophecies of

the end of the world.


In the countdown to the 29 March eclipse, for example, an Islamic “scholar”,

a Mallam Muniru Hamidu, declared that the world was going to end because it

is written in the Qur’an that when the end of the world got nigh, “God would

cause the sun and the moon to come together”. Other religious books such as

the Christian Bible connects eclipses with facts such as the Final Judgment.

One of the signs is the descent of darkness in the daytime. 109

The image below, obtained from the International Space Station, 230 miles

above the planet, was positioned to view the umbral shadow cast by the Moon

as it moved between the Sun and Earth during the solar eclipse on March 29,

2006 CE. The astronaut image captures the umbral shadow across southern

Turkey, northern Cyprus, and the Mediterranean Sea. People living in these

regions observed a total solar eclipse in which the Moon completely covered

the Sun’s disk.

Fig. 36 - Eclipse in outer space. The Moon’s shadow passing

over the Earth during eclipse. Source: NASA.



The Sun sends energy to the Earth and other planets in our solar system as heat

and light, along with particles

that constitute the solar wind.

Therefore, the space between

the Earth and the Sun is not

empty, but filled with plasma -

an electrified “gas” composed

of ions, electrons and fields.

Energetic radiation within

this plasma coming from

the Sun would be dangerous

to human life if the Earth’s

surface was not shielded

by our atmosphere and its

geomagnetic field and space

plasma environment, 110 that

is, the magnetosphere.

Fig. 37 – Space plasma environment of the Sun and Earth.

Magnetic energy bursts near the solar surface hurl plasmas

outward from the Sun. Clear magnetic field structures appear

in light blue. Source: NASA.

The Earth’s magnetosphere and ionosphere is a plasma system. It is the region

in space defined by the interaction of solar plasmas with Earth’s dipole-like

magnetic field, extending from about 85 km above Earth’s surface to more than

60,000 km in the sunward direction and to several hundred Earth radii in the

anti-sunward direction. 111

As mentioned, the magnetosphere shields the Earth against space weather:

solar wind, solar flares, coronal mass ejections, solar energetic particles and

so on. Similar to our atmosphere, the magnetosphere is a huge magnetic field

with lines running along it and, at the poles, right to the planet itself. 112 The

solar wind interacts with the magnetosphere so that the side facing the Sun is

compressed and the side opposite to the Sun is elongated.

Amazingly, there are plasmas out to the far reaches of the solar system. Space

environments surrounding planets and their satellites are filled with plasmas

such as the solar wind, solar and galactic cosmic rays (high-energy charged

particles), and particles trapped in planetary magnetospheres. All planets, and


the solar system itself, have their own unique space plasma environments.

Plasma is also the state of matter inside

the Sun. Basically, what we see when we

observe a total eclipse of the Sun are huge

amounts of plasma being ejected from our

star to form the solar corona and the solar

wind. Look at this magnificent image of

the Sun and its corona taken by the SOHO

spacecraft (Fig. 38), in combination with

a ground-based image, during a period of

maximum solar activity.

But what are plasmas, anyway, and

where can we find them? Plasmas are

basically an electrically conducting,

interactive combination of uncharged

and charged particles, positive ions,

negative electrons, electric and magnetic

fields, constituting the fourth state of

matter (see

Plasma exists at very high temperatures,

thousands or perhaps millions of degrees. At these temperatures the atoms

break and individual elementary particles are free in space. 113

The fraction of uncharged particles in a plasma varies substantially, ranging

from more than 95% in the lower ionosphere to less than 1% in the solar wind

the continuous stream of plasma from the Sun. Plasmas conduct electricity

and have other properties that make them more than simply a type of electrical

‘gas.’ 114

On Earth, plasmas are very common. For example, they are used for fluorescent

lamps, arc lamps, and laboratory experiments in sealed chambers. Tiny

plasma discharge elements constitute the pixel arrays of plasma televisions.

And of course, lightning: brief, long-range electrical discharges through the

atmosphere. Lightning is part of a global electrical circuit that links the Earth’s

surface to the conducting ionosphere. There are plasmas inside our body as

well. Today, plasmas are beginning to be applied as well in medicine: surgery

without cutting and “bloodless scalpels” are now becoming a reality through


Fig. 38 – Composite images from the 2001

total solar eclipse. Three distinguished images

form this picture. In the center, an image

obtained from space; the intermediate picture

has been taken from the ground and the outermost

image shows the corona as seen from

space. In that year the Sun was in a period

of maximum activity, so the corona is notably

expanded. Source: ESA/NASA.

cold plasmas that can inactivate bacteria through a combination of free radicals,

charged particles, and ultraviolet radiation, which work together to disrupt the

integrity of bacterial cell membranes. 115

Travelling farther, more than 99% of the visible Universe is in the plasma

state, giving rise to Tony Peratt’s metaphor “Plasma Universe.” Actually, in

space, we can find plasmas in the interstellar and intergalactic medium, in

diffuse forms like nebulas and in more condensed and hotter forms like stars or

supernovas. 116 Much closer to home, energy from the Sun produce phenomena

such as auroras, rainbows, sunrises. 117

Fig. 39 – The plasma universe. Intense regions of star birth within the

Orion nebula appear in this Hubble image. All visible regions here and

most of the low-density regions in between are dominated by plasmas

containing neutral particles, ions, electrons and electric and magnetic

fields. Source: NASA.

Solar particles carry a magnetic field that can sometimes disrupting the

magnetosphere, causing magnetic storms or auroras. 118 In special, auroras

shimmer and glow in the polar regions of the Earth. They are also known as the

Northern and Southern lights. 119 According to Peratt and Strait (1999), auroras

are “indefinite, undulating sheets that move and dance (…) It is the visible

manifestation of huge, invisible electric currents embracing Earth. The aurora

is a natural plasma light show.”


These beautiful auroral displays result from solar wind plasmas that filter

through the magnetic field surrounding the Earth, eventually striking and

exciting ionospheric atoms or molecules and causing them to radiate different


Fig. 40 – Aurora. This image obtained in January 2005 shows a marvelous

aurora borealis over a gelid landscape in Alaska. Source: NASA.

Next time you have an opportunity to observe a total solar eclipse, or even some

beautiful aurora, be aware that you are witnessing a prime nearby spectacle of

the same plasma processes that pervade the cosmos - a window to the plasma




Writing a paper is such a special act - it is an act of love. We always wonder

how to make that better, but at some point we just have to stop, hoping readers

will enjoy that. Few significant accomplishments can be completed alone, so

that I would like to express here my gratitude to a few exceptional people who

have been fundamental to help me make this project a beautiful reality.

Fig. 41– Dr. Timothy E.

Eastman. Plasma physicist

and group manager at

NASA Goddard. Creator of

the Web site

First, I want to express my deep and special gratitude

to Dr. Timothy E. Eastman (Perot Systems at NASA

Goddard), my mentor and supervisor, who provided

full and unique guidance and support to make my

NASA internship possible. Dr. Tim is a brilliant

plasma physicist, and a wonderful person. He has

made a tremendous difference in my life, teaching me

fundamental professional, academic and life lessons.

I am very thankful to Dr.

Louis A. Mayo (SP Systems at

NASA Goddard), my mentor,

for our countless pedagogical

and scientific discussions,

which largely enriched the

research. He is a great astronomer and space science

education spacialist, and a special person who has

greatly contributed to my internship experience at


Fig. 42 – Dr. Lou Mayo. Astronomer,

space science education

specialist at NASA Goddard.

Many thanks to Ms. Constance Carter, Head of the Science Reference Section

of the Science, Technology and Business Division of the Library of Congress

- LOC, who assisted me in finding several outstanding sources, which greatly

contributed to the quality of this paper.


I am deeply thankful to the guidance of Dr. Fred

Espenak (NASA Goddard) who, for very good

reasons, is known as “Mr. Eclipse”. Dr. Espenak

kindly provided singular guidance and assistance

during this research, indicating valuable sources,

and making available various images from his

eclipse-dedicated Web sites, books and papers.

Other distinguished NASA specialists were

exceptionally generous by collaborating to the

enhancement of this project: Dr. Troy Cline, for his

support in the production of this paper Web site and

podcasts; M.Sc. Rita Johnson, for her partnership

in the production of the Portuguese podcast; Dr.

Robert L. Kilgore, and Dr. Glen A. Asner, for their

critical reading and suggestions to the paper; and Dr. Jay Friedlander, who

provided design and artistic support.

Thanks to all NASA people who made my internship experience just wonderful

and unforgettable!

I would also like to express my gratitude to the Brazilian Ministry of Education

(MEC), my sponsors and reference people in Brazil and abroad, for all their

support that was essential to help me accomplish this project.

My special thanks to my parents and masters, Mrs. Antonia Reis (who already

passed away) and Mr. Antonio Oliveira Reis, whose unconditional love,

continued support and encouragement have been essential to help me reach

my dreams.

Foremost, I want to thank God for the unique combination of gifts, opportunities,

and for introducing such special people in my life. He has been opening doors

to turn my “pathway to the stars” into such a wonderful reality – the lifetime

passion I always dreamed about: NASA!


Fig. 43 – Dr. Fred Espenak. Astronomer,

NASA Goddard, creator

of the Web site

References 1

[1] Andrews, Tamra, Wonders of the Sky - Wonders of Nature: Natural

Phenomena in Science and Myth, Westport: Libraries Unlimited, 2004.

[2] Baikouzis, Constantino and Magnasco, Marcelo O. “Is an eclipse described

in the Odyssey?” PNAS, v. 105, n. 26, July 1, 2008, p. 8823-8828. Available at:

[3] Boston, Anne, “At Another Eclipse, a Star Was Born,” New Statesman, v.

128, August 9, 1999, p. 16.

[4] Brewer, B., Eclipse, Seattle: Earth View, 1991.

[5] Brunier, S., Luminet, J. P., Glorious Eclipses: Their Past Present and

Future, Cambridge University Press, 2000.

[6] Chambers, George F., The Story of Eclipses, New York: D. Appleton and

Company, 1902.

[7] Duodu, Cameron, “The Day the World Failed to End-Again,” New African,

n. 451, May 2006, p. 46+.

[8] Eastman, Timothy E., “A survey of plasmas and their applications,” Plasma

Physics Applied, 2006, p. 11-26

[9] Eddy, John A., “The Great Eclipse of 1878,” Sky and Telescope, June 1973.

[10] Espenak, Fred. Fifty Year Canon of Solar Eclipses, Washington, DC:

NASA, Scientific and Technical Information Office, 1987.

[11] Fotheringham, J. K., “A Solution of Ancient Eclipses of the Sun,” Monthly

Notices of the Royal Astronomical Society. NASA Astrophysics Data System,

v. 81, November 1920. Available at:


[12] Glaser, David and Beals, Kevin, Living With a Star: from sunscreen

to space weather: teacher’s guide for grades 6-8, Berkeley: University of

California, 2003.

[13] Hajar, Rachel, “The Dragon: Mythical Beasts of the Middle East,” Part 2,

World and I, v. 14, January 1999, p. 218.

[14] Humphreys, J. Colin, Waddington, W. G., “Dating the Crucifixion,”

Nature, v. 306, n. 5945, December 22, 1983, p. 743-746.

[15] Ibid, “The Date of the Crucifixion,” JASA, n. 37, March 1985, p. 02-10.

[16] Ionides, Stephen A. and Ionides, Margareth L., Stars and Men, Indianapolis,

New York: Bobbs-Merril, 1939.

1 The Web sites accessed for this project are indicated in the Footnotes section.


[17] Lang, Kenneth R., Sun, Earth and Sky, New York: Springer-Verlag, Berlin

Heidelberg, 1997.

[18] Littell, Eliakim and Littell, Robert S., The Living Age, Boston: Son &

Company, 1868.

[19] Littman, Mark, Willcox, Ken and Espenak, Fred, Totality: Eclipses of the

Sun, ed. 2, New York, Oxford: Oxford University Press, 1999.

[20] Margulis, Lynn and Punset, Eduard, Suzuk, David T. (Contributor), Mind,

Life, and Universe: Conversations with Great Scientists of Our Time, White

River Junction: Chelsea Green, 2007.

[21] Mitchel, S. A., Eclipses of the Sun, New York: Columbia University Press,

ed. 5, 1951.

[22] Mitchell, Maria, “The Total Eclipse of 1869,” from “Hours at Home for

October,” APS Online, v. 26, n. 37, Nov. 13, 1869, p. 587.

[23] NASA RP 1383 Total Solar Eclipse of 1999 August 11, April 1997, p. 19.

[24] Needham, Joseph, Science and Civilisation in China, New York, Oxford:

Cambridge University Press, 2008.

[25] Newton, Robert R., Medieval Chronicles and the Rotation of the Earth,

Baltimore: Johns Hopkins University Press, 1972.

[26] Peratt, Anthony and Strait, G. Carroll, “At Home in the Plasma Universe,”

World and I, v. 14, September 1999.

[27] Peratt, Anthony L., Physics of the Plasma Universe, New York: Springer-

Verlag, 1991.

[28] Schaefer, Bradley E., “Lunar Eclipses That Changed the World,” Sky and

Telescope, December 1992, p. 639-642.

[29] Ibid, “Solar Eclipses That Changed the World,” Sky and Telescope, May

1994, p. 36-39.

[30] Ibidem, Q J R. Astr. Soc., v. 31, 1990, p. 53-67.

[31] Scientific American, “The Total Eclipse of the Sun,” APS Online, v.

XXXIX, n. 04, July 27, 1878, p. 56.

[32] Sinnott, Roger W., “Columbus and an Eclipse of the Moon,” Sky and

Telescope, October 1991, p. 437-440.

[33] Smith, George and Thackeray, William M., The Cornhill Magazine, v. 18,


[34] Soares, Maria Norma Maia, Eclipse de 1919: Múltiplas Visões, ed. 2,

Sobral: Edições UVA, 2003.

[35] Steel, Duncan, Eclipse: the Celestial Phenomenon that Changed the


Course of History, Washington, DC: Joseph Henry Press, 2001.

[36] Stephenson, F. Richard, Historical Eclipses and Earth’s Rotation,

Cambridge, UK; New York, Cambridge University Press, 1997.

[37] The Oxford English Dictionary: A New English Dictionary on Historical

Principles. Volume III, Oxford University Press, 1969.

[38] The Washington Post 1877, “New Theory of Space,” 14 Dec. 1919. P. E5.

[39] Twain, Mark, A Connecticut Yankee in King Arthur’s Court, New York,

London, Harper & Brothers, 1889.

[40] Ibid, The Adventures of Huckleberry Finn, New York, P. F. Collier & Son,


[41] Wilford, John Noble, “Homecoming of Odysseus May Have Been in

Eclipse,” The New York Times, June 24, 2008.

[42] Wilson, Robert. Astronomy through the Ages: The Story of the Human

Attempt to Understand the Universe, London, CRC Press, 1997.

[43] Wolff, Larry, Inventing Eastern Europe - The Map of Civilization on the

Mind of the Enlightenment, Stanford University Press, 1994.

[44] Wright, Helen, Sweeper in the Sky: the Life of Maria Mitchell First Woman

Astronomer in America, New York: The Macmillan Company, 1949.



1 Extracted from the “Stanford Solar Center” Web site, maintained by the Stanford Solar

Center ©2008,

2 Andrews, 2004.

3 Brunier and Luminet, 2000.

4 Steel, 2001.

5 Hajar, 1999.

6 Brunier and Luminet, 2000.

7 Andrews, 2004.

8 Brunier and Luminet, 2000.

9 Wilson, 1997.

10 The outermost layer of the Sun’s atmosphere, visible to the naked eye during a total solar

eclipse, can also be observed through special filters and X-ray cameras aboard satellites.

The corona is composed of hot plasmas, up to 1.5 million degrees centigrade, and generates

the solar wind.

11 Extracted from the “NASA Sun Earth Day - Eclipse” Web site, http://sunearthday.nasa.


12 Wilson, 1997.

13 Ibid.

14 Needham, 2008.

15 Ibid.

16 Littmann et al., 1999.

17 Extracted from theEclipses” Web site,

18 Extracted from the “Crystalinks” Web site, maintained by Ellie Crystals ©1995-2008,

19 Newton, 1972.

20 Espenak, 1987.

21 Ibid.

22 Ibidem.

23 Ibidem.

24 Extracted from the “Crystalinks” Web site (Idem 18).

25 Eclipse predictions by Fred Espenak, from NASA Goddard.

26 Extracted from the “NASA Eclipse Web site,”

27 Glaser & Beals, 2003.

28 Pitts, 1993 in NASA, 1997.


29 Extracted from the “Mr. Eclipse” Web site, maintained by Fred Espenak, http://www.

30 Littmann et al., 1999.

31 Twain, 1918.

32 Brunier and Luminet, 2000.

33 Needham, 2008.

34 Ibid.

35 Ibidem.

36 Brunier and Luminet, 2000.

37 Stell, 2001.

38 Mitchel, 1951.

39 Baikouzis & Magnasco, 2008.

40 Wilford, 2008.

41 Brunier and Luminet, 2000.

42 Fotheringham, 1920.

43 Ionides and Bobbs-Merrill, 1939.

44 Wikipedia.

45 According to Fred Espenak, from NASA Goddard, the Saros cycle consists of a period of

18 years, 11 days and 8 hours. If one goes forward or backward within this period, another

solar eclipse, very similar to the first one, will be encountered. It will occur approximately

at the same season, and with approximately equal distances to the Moon-Earth-Sun system.

The Babylonians and the Chaldeans discovered it by keeping records of lunar eclipses. The

Saros family of eclipse is imperfect, presenting northward or southward shifts.

46 The mean time for one lunar phase cycle (i.e., the synodic period of the Moon) is

29.530.589 days, or 29 days, 12 hours, 44 minutes, 3 seconds. More specifically, a lunation

is also commonly defined as the mean time between successive new moons. Extracted


47 Needham, 2008.

48 Steel, 2001.

49 Chambers, 1902.

50 Brewer, 1991.

51 Steel, 2001.

52 Brewer, 1991.

53 Steel, 2001.

54 Ionides & Ionides, 1939.

55 Chambers, 1902.

56 Ionides & Ionides, 1939.


57 Chambers, 1902.

58 Considering the hypothesis of November 24, 29 CE.

59 Humphreys and Waddington, 1983.

60 Brunier and Luminet, 2000.

61 Idem.

62 Humphreys and Waddington, 1985.

63 Duncan, 2001.

64 Schaefer, 1990.

65 Humphreys and Waddington, 1983.

66 Schaefer, 1994.

67 Chambers, 1902.

68 Idem.

69 Steel, 2001.

70 Stephenson, 1997.

71 Brunier and Luminet, 2000.

72 Idem.

73 Ionides & Ionides, 1939.

74 Brunier and Luminet, 2000.

75 Chambers, 1902.

76 Littell & Littell, 1868.

77 Schaefer, 1992.

78 Brunier and Luminet, 2000.

79 Idem.

80 Steel, 2001.

81 Twain, 1889.

82 Wolff, 1994.

83 Smith, 1868.

84 Extracted from “Eclipse Quotations,” in the “Mr. Eclipse” Web site, maintained by Fred


85 Chambers, 1902.

86 Brunier and Luminet, 2000.

87 Idem.

88 Extracted from the “Social Studies for Kids” Web site, maintanned by David White,

89 Extracted from the “Inventor Biographies” Web site, maintained by NetIndustries, LLC



57 Chambers, 1902.

58 Considering the hypothesis of November 24, 29 CE.

59 Humphreys and Waddington, 1983.

60 Brunier and Luminet, 2000.

61 Ibid.

62 Humphreys and Waddington, 1985.

63 Duncan, 2001.

64 Schaefer, 1990.

65 Humphreys and Waddington, 1983.

66 Schaefer, 1994.

67 Chambers, 1902.

68 Ibid.

69 Steel, 2001.

70 Stephenson, 1997.

71 Brunier and Luminet, 2000.

72 Ibid.

73 Ionides & Ionides, 1939.

74 Brunier and Luminet, 2000.

75 Chambers, 1902.

76 Littell & Littell, 1868.

77 Schaefer, 1992.

78 Brunier and Luminet, 2000.

79 Ibid.

80 Steel, 2001.

81 Twain, 1889.

82 Wolff, 1994.

83 Smith, 1868.

84 Extracted from “Eclipse Quotations,” in the “Mr. Eclipse” Web site, maintained by Fred


85 Chambers, 1902.

86 Brunier and Luminet, 2000.

87 Ibid.

88 Extracted from the “Social Studies for Kids” Web site, maintanned by David White,

89 Extracted from the “Inventor Biographies” Web site, maintained by NetIndustries, LLC


90 Ibid 88.

91 Schaefer, 1994.

92 Brunier and Luminet, 2000.

93 Ibid.

94 Schaefer, 1992.

95 Brunier and Luminet, 2000.

96 Scientific American, 1878.

97 Eddy, 1973.

98 Extracted from “The Vassar Encyclopedia online,” Web site, maintained by the Vassar’s

College Historian,

99 Wright, 1949.

100 Ibid.

101 Steell, 2001.

102 Soares, 2003.

103 Boston, 1999.

104 Schaefer, 1994.

105 Brunier and Luminet, 2000.

106 Steel, 2001.

107 Extracted from the ESA Web site,


108 Steel, 2001.

109 Doudu, 2006.

110 Lang, 1997.

111 Peratt, 1992.

112 Glaser and Beals, 2003.

113 Margulis and Punset, 2007.

114 Extracted from the “Coalition for Plasma Science” Web site, maintained by the Coalition

for Plasma Science ©1999, 2000,

115 Extracted from the “Perspectives on Plasmas - the fourth state of matter” Web site,

maintained by Tim Eastman, Plasmas International ©1999, 2004,

116 Idem.

117 Extracted from the “Stanford Solar Center” Web site, maintained by the Stanford Solar

Center ©2008,

118 Glaser and Beals, 2003.

119 Extracted from the “Traditions of the Sun” Web site, maintained by UC Regents ©2005,


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